Consumption Of Internal Combustion Engines Research Articles

Friction between pin and roller of a truck’s valvetrain

In order to minimize the fuel consumption in internal combustion engines, the frictional losses must be minimized between the moving parts such as the sliding bearings. In this study, the sliding friction between the pin and roller in a heavy duty truck engine’s valvetrain has been investigated. Three combinations of production components with different surface treatment were used: steel pin with steel roller, steel pin with WS2 coating inside the roller and PVD coated steel pin with steel roller.In-house test rig was used, enabling controlled conditions close to the real engine. A new method for alignment using a laser scanner was introduced together with high resolution tactile measurements of radial displacement during test. Surface topography of pins and rollers was measured before test with a mechanical stylus instrument. The WS2 showed 3.1 times and the PVD showed 2.5 times lower friction than the steel type at low speeds. Even though the friction reduction of WS2 over the PVD is not large, the important advantage is that the WS2 can be manufactured at lower costs than the PVD one. Good correlations among the friction, initial roughness and radial displacements were also found.

Analysis of Soot from the Use of Butanol Blends in a Euro 6 Diesel Engine

The use of advanced fuels must increase from 0.5 to 3.6% of the total fuel consumption in internal combustion engines according to the forthcoming European directive. In this regard, alcohols that ...

Evaluation and transient control of an advanced multi-cylinder engine based on partially premixed combustion

Modern transportation requires advanced powertrain systems to reduce the production of greenhouse gas CO2. Partially premixed combustion (PPC) is one of the most promising methods to achieve low emission and low fuel consumption of internal combustion engines. The present paper evaluated the effects of the calibration parameters on the efficiency and emissions of a multi-cylinder engine using PPC during stable operations, and the performance of the engine during transient operations. The peak gross indicated efficiency of 51.5% and the peak net indicated efficiency of 48.7% were achieved under stable operating conditions. The transient results also demonstrate an average net indicated efficiency of 47.5%. The nitrogen oxides (NOx), carbon monoxide (CO), and hydrocarbon (HC) conform with the Euro VI emission legislation in the case of most transient operations except some low load points.

Fuel consumption in an air blower for agricultural use under different operating conditions

ABSTRACT Evaluation of fuel consumption in internal combustion engines (ICE) of agricultural machinery and equipment is important in determining the performance under various operating conditions, especially when using biofuels. This study consisted of experimental evaluation of the gasoline (petrol)/ethanol consumption in a two-stroke 1-cylinder ICE, Otto cycle, functioning as an air blower for agriculture and related applications. A methodology for tests of non-automotive ICE, based on ABNT/NBR technical standards, was considered. The presented results refer to operation with commercial and non-commercial fuel blends. Characteristic curves for the tested equipment are presented, identifying consumption conditions and trend in the whole operating range of angular speeds (RPM), for five fuel blends (gasoline/ethanol). For the operating conditions of minimum and maximum angular speeds, 20 and 30% ethanol blends had the highest and lowest fuel consumptions, respectively.

Effect of Hydrogen–Oxygen Mixture Addition on Exhaust Emissions and Performance of a Spark Ignition Engine

In the last decade, there has been a major ascending interest in reducing the polluting concentration and fuel consumption of internal combustion engines. The solution proposed in this research project was to integrate a hydrogen and oxygen mixture \({{\rm H}_{2}/{\rm O}_{2}}\), obtained through an electrolysis process of water, as supplementary fuel, in a 93 cm\({^{3}}\) gasoline engine. Several experimental tests were carried out under different engine loads (0, 20, 50, 80 and 100 %) in order to investigate the effect of \({{\rm H}_{2}/{\rm O}_{2}}\) addition on the engine performance characteristics and the exhaust gas concentration. At engine loads more than 20 %, tests showed that adding \({{\rm H}_{2}/{\rm O}_{2}}\) reduced the brake-specific fuel consumption by an average of 7.8 %. They also showed that the alternative fuel was very efficient in reducing the concentration of pollutant emissions in the exhaust gases: hydrocarbon (HC) concentration diminished by an average of 18 %, carbon monoxide (CO) concentration decreased by an average of 31.8 %, and \({{\rm CO}_{2}}\) concentration decreased up to 30 %. However, at low engine loads, \({{\rm NO}_{x}}\) concentration decreased by an average of 26 %, but it increased significantly with the increase in engine loads (exceeding 80 %).

Blow-by and tribological performance of piston ring pack during cold start and warm idle operations

To reduce the fuel consumption of internal combustion engines, more attention has been paid to the tribological performance of the piston ring pack during the cold start and idle operations. In this research, a numerical model considering the cylinder liner deformation and the piston ring conformability is developed to predict the blow-by, lubrication, friction and wear of the piston ring pack under different operating conditions. The gas flow rate, inter-ring gas pressures, minimum oil film thickness, frictional force and wear load during cold start are calculated and compared with those during warm idle operating conditions. The results show that cylinder liner deformation and piston ring conformability together obviously affect blow-by and other tribological performance. Meanwhile, it is found that friction loss is larger during cold start than during warm idle operating conditions. However, the wear process is more severe during warm idle operation than during cold start. From this research, the blow-by and tribological performance of the piston ring pack during cold start and warm idle operations are understood more deeply.

대형 디젤 엔진의 연비 향상을 위한 Miller Cam 평가

Miller timing is one of the promising ways which can improve the fuel consumption of internal combustion engines. Indeed, Miller timing employing an early intake valve close is widely applied to large diesel and gas engines to enhance performance and reduce NOx emissions. In this study, performance evaluation is carried out by 1-D cycle simulation in order to estimate the effect of Miller CAM timing before BDC for a 32 L turbocharged diesel engine. To optimize Miller CAM timing, a single stage turbocharger is matched with an early intake valve close since boost pressure is a significant parameter that can control compression work in a turbocharged engine. The engine simulation result shows that there is enough potential to improve fuel consumption rate and also reduce NOx emissions at the same time.Abstract here.

A new and efficient mechanism for spark ignition engines

In this paper a new symmetrical crank and slider mechanism is proposed and a zero dimensional model is utilized to study its combustion performance enhancement in a four-stroke spark ignition (SI) engine. The main features of this new mechanism are superior thermodynamic efficiency, lower internal frictions, and lower pollutants. Comparison is made between its performance and that of the conventional four-stroke SI engines. Presented mechanism is designed to provide better fuel consumption of internal combustion engines. These advantages over standard engine are achieved through synthesis of new mechanism. Numerical calculation have been performed for several cases of different mechanism parameters, compression ratio and engine speed. A comprehensive comparison between their thermodynamic processes as well as vibration and internal forces has been done. Calculated efficiency and power diagrams are plotted and compared with performance of a conventional SI engine. Advantages and disadvantages of the proposed mechanism are discussed in details.

Design Methodology of Camshaft Driven Charge Valves for Pneumatic Engine Starts

Idling losses constitute a significant amount of the fuel consumption of internal combustion engines. Therefore, shutting down the engine during idling phases can improve its overall efficiency. For driver acceptance a fast restart of the engine must be guaranteed. A fast engine start can be performed using a powerful electric starter and an appropriate battery which are found in hybrid electric vehicles, for example. However, these devices involve additional cost and weight. An alternative method is to use a tank with pressurized air that can be injected directly into the cylinders to start the engine pneumatically. In this paper, pneumatic engine starts using camshaft driven charge valves are discussed. A general methodology for an air-optimal charge valve design is presented which can deal with various requirements. The proposed design methodology is based on a process model representing pneumatic engine operation. A design example for a two-cylinder engine is shown, and the resulting optimized pneumatic start is experimentally verified on a test bench engine. The engine’s idling speed of 1200 rpm can be reached within 350 ms for an initial pressure in the air tank of 10 bar. A detailed system analysis highlights the characteristics of the optimal design found.

The effects of low sulfated ash, phosphorus and sulfur oils on camshaft/tappet tribocouples with various diamond-like-carbon coated tappets in motored and fired engines

This work was conducted as part of an EU FP-7 project ‘Tailoring of Tribological Interfaces for Clean and Energy-Efficient Diesel and Gasoline Powertrains’. The primary goal of this work is to reduce fuel consumption in internal combustion engines by the use of bespoke surface coatings and lubricants. Earlier work within the project had defined a series of oils and coatings to be evaluated in the final stage of the project. The results reported in this paper have used the OM646LA engine to evaluate wear and a motored cylinder head manufactured from the same engine type to evaluate the friction performance of coating/oil combinations. The coatings were applied to the tappets in the valvetrain and tested against uncoated camshafts. It will be shown that diamond-like-carbons can offer frictional benefits over an all-steel system and that the choice of lubricant can incrementally reduce friction further. It will also be shown that while some diamond-like-carbon coatings are durable enough to survive the fired engine test intact, others are completely removed; interestingly, in all cases, the wear on the counter-surface, the cam lobes, was in the order of a magnitude lower than for the standard all-steel system. Copyright © 2014 John Wiley & Sons, Ltd.

Minimum data requirement for neural networks based on power spectral density analysis.

One of the most critical challenges ahead for diesel engines is to identify new techniques for fuel economy improvement without compromising emissions regulations. One technique is the precise control of air/fuel ratio, which requires the measurement of instantaneous fuel consumption. Measurement accuracy and repeatability for fuel rate is the key to successfully controlling the air/fuel ratio and real-time measurement of fuel consumption. The volumetric and gravimetric measurement principles are well-known methods for measurement of fuel consumption in internal combustion engines. However, the fuel flow rate measured by these methods is not suitable for either real-time control or real-time measurement purposes because of the intermittent nature of the measurements. This paper describes a technique that can be used to find the minimum data [consisting of data from just 2.5% of the non-road transient cycle (NRTC)] to solve the problem concerning discontinuous data of fuel flow rate measured using an AVL 733S fuel meter for a medium or heavy-duty diesel engine using neural networks. Only torque and speed are used as the input parameters for the fuel flow rate prediction. Power density analysis is used to find the minimum amount of the data. The results show that the nonlinear autoregressive model with exogenous inputs could predict the particulate matter successfully with R(2) above 0.96 using 2.5% NRTC data with only torque and speed as inputs.

Predictive Power Management Strategy for a PHEV Based on Different Levels of Trip Information

Increasing restrictions on emissions and fuel consumption of internal combustion engines and availability of fast processors have resulted in an increased interest in using model predictive control (MPC) for vehicle powertrain control applications. This approach is capable of fast and near-optimal control of hybrid electric vehicle powertrains. In this article, different MPC power management strategies for a plug-in hybrid electric vehicle are evaluated, with different levels of trip information available to the controller, based on fuel economy.

Design Methodology of Camshaft Driven Charge Valves for Pneumatic Engine Starts

Idling losses comprise a significant amount of the fuel consumption of internal combustion engines. Therefore, shutting down the engine during idling phases can improve their overall efficiency. For driver acceptance a fast restart of the engine must be guaranteed. A fast engine start can be realized using a powerful electric starter and an appropriate battery which are found for example in hybrid electric vehicles. However, these involve additional cost and weight. An alternative method is to use pressurized air stored in a tank that can be injected directly into the cylinders to start the engine pneumatically. In this paper pneumatic engine starts using camshaft driven charge valves are discussed. A general methodology for an air-optimal charge valve design is presented which can tackle various requirements. The proposed design methodology is based on a process model representing pneumatic engine operation. A design example for a two-cylinder engine is shown and the resulting optimized pneumatic start is experimentally verified on a test bench engine. The engine's idling speed of 1200 rpm can be reached within 350 ms for an initial pressure in the air tank of 10 bar.

Refined simulation of friction power loss in crank shaft slider bearings considering wear in the mixed lubrication regime

Friction reduction is a fundamental factor in decreasing fuel consumption of internal combustion engines. During the design stage of the engine the simulation of friction in the crank mechanism plays a vital role to develop optimum solutions. Due to the interaction of oil and elastic structures with rough surfaces in slider bearings, complex simulation models have to be used for representing the relevant physical behavior. The following article is focused on crank shaft slider bearings of large engines. The article describes a procedure evaluated by measurements showing how to model wear profiles of slider bearings to reach a high quality friction forecast. A fundamental influencing factor of bearing friction is given by the mixed lubrication regime and it is considered in the simulation model as part of asperity contact friction and hydrodynamic friction. Further effects result from the compliance in radial and width directions of the bearing structure and the wear of the bearing surface. Furthermore, the specific operating conditions of the slider bearing such as load, temperature, shaft speed and oil characteristics are essential and have to be taken into account. The objective of this investigation is to propose the wear profile of the bearing surface for the simulation model to be treated iteratively, where simulation results for the amount of mixed lubrication are successively assessed. For this purpose an iterative procedure is introduced and validated by measurements on a slider bearing test rig. The applied simulation method is based on elastic multi-body systems; the lubrication film contact is calculated based on Reynolds differential equation via the pressure balance calculated iteratively in the time domain. The model accounting for the mixed lubrication regime is based on the theory of Greenwood and Tripp.

STABILITY ANALYSIS OF RESIDUAL-AFFECTED HCCI USING CONVEX OPTIMIZATION

Homogeneous Charge Compression Ignition (HCCI) is a promising methodology for simultaneously reducing emissions and fuel consumption in internal combustion engines. One approach to achieving HCCI is via reinduction or trapping of hot combustion gas, which results in cycle-to-cycle coupling between subsequent engine cycles through the exhaust gas temperature. A consequence of this coupling are sections of the state space which exhibit either stable or unstable responses to perturbations. This paper exploits the characteristics of a previously validated 2-input 2-output control model of residual-affected HCCI to analytically determine the area of the state space which is stable to perturbation of either combustion timing or in-cylinder pressure evolution. As efforts to control and expand the operating range of HCCI continue, analytical stability tools like that developed here will likely play an increasingly important role.

Comparative investigations of oil consumption and oil emissions on a spark ignition engine

Determining the oil consumption of internal combustion engines presents a challenge to every engine test engineer due to the complex interactions. In a joint project set up by Federal Mogul Burscheid GmbH and General Motors Powertrain Europe it was proposed to study the behavior of a gasoline engine with respect to sump oil consumption and oil emissions in the exhaust gas. To measure the emissions a new online measurement system supplied by Automobil-Pruftechnik Landau was used which enables oil emissions to be measured directly in the exhaust gas of a combustion engine.